This invention is directed to an improvement in a Cartesian diving toy and a receptacle in which the toy is used. The Cartesian diver is improved by including as part of the air chamber of the diver an invaginated section which is convoluted and is capable of extending and shortening in direct response to fluid pressure outside of the air chamber. The receptacle is improved by incorporating means allowing essentially complete purging of air from within the receptacle.
Many Cartesian diving toys are known. The majority of the earlier Cartesian diving toys were limited to rising and falling in a vertical manner within a body of a suitable fluid, such as water. The Cartesian diving principle was utilized in these toys to change their density with respect to the liquid they were suspended in by moving a portion of that liquid in and out of the toy, depending on the pressure of the suspending liquid. In U.S. Pat. No. 2,345,243 a Cartesian diving toy was described which, in addition to performing simple vertical up and down movements, was capable of exhibiting certain other movements. This toy was equipped with a small metal bellows to which a weight was attached. As the bellows moved in response to pressure in the surrounding fluid, the weight was displaced within the body to change the center of gravity such that the body (a human figure) when descending was oriented with its head down and when ascending had its head raised.
In attempts to better mimic the actual movement of an aquatic animal and/or a diver, improvements were made in U.S. Pat. No. 3,071,375 to Cartesian diving toys. In this patent a fish was equipped with a body having spring members located on each of its sides. These spring members extended to and attached to the tail. By increasing and decreasing the pressure of the suspending liquid in which the fish was placed, the tail of the fish was caused to move sideways and thus better mimicked the actual movement of a fish.
In a further improvement to a Cartesian diving toy, U.S. Pat. No. 3,382,606 described a diving bell type action figure. A horizontal component of movement was introduced into the Cartesian diver of this patent by incorporating a small propeller attached to a chamber which was caused to spin by discharge of water through a jet in response to decrease of pressure in the suspending liquid.
In U.S. Pat. No. 3,924,350 the Cartesian diving principle was further refined such that a small aquatic object, a fish, was able to be directed within the suspending liquid in such a manner that it more clearly mimicked the swimming action of an actual fish. In this patent, horizontal movement of the fish was accomplished via movement of a diaphragm in response to a pressure differential set up in the suspending liquid. The movement of the diaphragm was linked via a bell crank to the tail fin of the fish causing the tail of the fish to move about the laterial axis of the toy to propel the fish. In addition to improvements to the Cartesian diver, in this patent, improvements were also made to the tank which held the suspending liquid. These improvements were directed to a method which facilitated removal of the gas within the tank.
It is considered advantageous for the suspending liquid to be gas free such that the gas contained within the Cartesian diver itself will be the only gas which is expanded or contracted with respect to a pressure differential within the suspending liquid. In this way all of the energy in expanding or contracting of the gas by the suspending liquid can be utilized by the Cartesian diving toy to move the propulsion member of the toy. If, in fact, other gas exists within the suspending liquid, higher pressure differentials must be exerted on that liquid in order to accomplish the same amount of movement of the Cartesian diver.
While it is considered that the disclosures of the above U.S. patents are very utilitarian, at least in two areas certain problems related to Cartesian diver toys have not been solved. The first of the problems is directed to membranes separating the air chambers of the divers from the supporting liquids and the second problem is directed to removing gas from within the receptacle wherein the Cartesian diver is used.
The prior known Cartesian diver toys have utilized stretchable membranes to divide their air chambers from the supporting liquids. Unfortunately, these membranes are not uniform in response to pressure gradients created within the supporting liquids. When the membrane is essentially unstretched, its movement in response to a pressure differential created in the supporting liquid is different than when it is streteched. Once the membrane is stretched it offers resistance to further stretching. Additionally, a temperature increase in the supporting liquid will cause deviation of any linkages attached to the membrane from a neutral or centralized position. If these linkages are so deviated when a true response or movement of these linkages is desired upon changing of the pressure in the supporting liquid the linkage is incapable of fully responding. Further, the membranes often deform asymmetrically relative to their center line in a back and forth direction. Any linkages connected to such an asymmetric deviating membrane, of course, will not operate properly.
With regard to degassing of the container or receptacle utilized to hold the supporting liquid, U.S. Pat. Nos. 3,071,375 and 3,382,606 are silent as to how the last amounts of gas are eliminated from within their reservoirs. U.S. Pat. No. 3,924,350 makes significant steps to eliminate gas from their reservoir. A stopper is described in this patent which is purported to perform this function. The pressure bulb utilized to create a pressure gradient within the suspending liquid within the reservoir, however, does not benefit from the placement or shape of the stopper utilized to purge the reservoir. The connection between the pressure bulb and the stopper occurs at the lowest point in the pressure bulb conduit system. Therefore, it is impossible for gas to excape upwardly out of the pressure bulb. Since it is physically impossible for both the pressure bulb and the reservoir to be inverted at the same time such that the stopper is at the highest point with respect to each of them and can degas both of them, only one of them at a time can be purged of gas.